Many of the drugs used arc not completely metabolized in the human body and with urine and faces arc introduced into the sewage system. Finally, due to their incomplete removal during the conventional wastewater treatment process (CWTP), they can be released into the receiving water. One of the medicaments frequently detected in surface water is diclolcnac. The present study addresses the problem of diclofcnac removal in various aquatic samples using advanced oxidation processes (AOPs). The experiments were performed in distilled water and in biologically treated wastewater. The following AO Ps were applied: Fenlon 's reagent, UVand UV/H2O2-processes. The concentration of diclolcnac in distilled water corresponded to the concentration of this drug in human urine (ca. 20 mg-dm'). The real wastewater samples contained diclofcnac concentrations ranging from 630 to 790 ng-dm-'. The photodcgradation of diclolcnac was carried out in the photorcactor with a medium pressure Hg-vapor lamp (400 W). In the Fcnton's reaction different molar ratiosof H2O2/Fc'' were used. The diclotcnac mineralization (TOC removal) strictly depended on the amount of 1-1,0, applied in the Fcnton's reaction. Diclofcnac was rapidly degraded by direct photolysis (UV) and in UV/H2O2,-process both in distilled water and in wastewater samples. The results proved that the advanced oxidation processes arc cflcctive in diclofcnac removal from aquatic samples. The pseudo first order rate constants It)!' diclolcnac photodcgradation were determined.

Polycyclic aromatic hydrocarbons (PAHs) belong to the group of recalcitrants that on reaching wastewater can irreversibly inhibit some sensitive biological processes in activated sludge such as nitrification. This situation leads to wastewater treatment failure due to the influence of these substances on bacteria responsible for important biochemical processes. Observation of the changes in bacterial diversity using molecular tools, such as denaturing gradient gel electrophoresis (DGGE), could be the first step in finding a way of preventing wastewater treatment failure. The aim of this experiment was to monitor bacterial biodiversity in a membrane bioreactor (MBR) dealing with synthetic wastewater contaminated with high concentration of petroleum organic compounds (POCs) and to study the influence of POCs contamination on bacterial changeability in activated sludge. COD removal in investigated membrane bioreactors was at a level of 93%. The organics removal efficiency was not affected by the maximal tested dose of petroleum contamination ( l OOO μl POCs/l of wastewater) and the MBRs wastewater treatment performance was undisturbed. DGGE analysis revealed that the biodiversity fluctuated slightly in control MBR, while in experimental MBR the biodiversity index decreased drastically after adding the highest experimental concentration of POCs. These results suggest that concentrations of POCs at levels from 50 μl/l to 500 μl/l stimulate biodiversity growth, while the concentration I OOO μI POCs/1 of wastewater seems to inhibit the most sensitive processes in wastewater treatment by influencing the bacterial biocenosis.

Nitritation, the first stage of ammonia removal process is known to be limiting for total process performance. Ammonia oxidizing bacteria (AOB) which perform this process are obligatory activated sludge habitants, a mixture consisting of Bacteria, Protozoa and Metazoa used for biological wastewater treatment. Due to this fact they are an interesting bacterial group, from both the technological and ecological point of view. AOB changeability and biodiversity analyses both in wastewater treatment plants and lab-scale reactors are performed on the basis of 16S rRNA gene sequences using PCR-DGGE (Polymerase Chain Reaction – Denaturing Gradient Gel Electrophoresis) as a molecular biology tool. AOB researches are usually led with nested PCR. Because the application of nested PCR is laborious and time consuming, we have attempted to check the possibility of using only first PCR round to obtain DGGE fingerprinting of microbial communities. In this work we are comparing the nested and non-nested PCR-DGGE monitoring of an AOB community and presenting advantages and disadvantages of both methods used. The experiment revealed that PCR technique is a very sensitive tool for the amplification of even a minute amount of DNA sample. But in the case of nested-PCR, the sensitivity is higher and the template amount could be even smaller. The nested PCR-DGGE seems to be a better tool for AOB community monitoring and complexity research in activated sludge, despite shorter fragments of DNA amplification which seems to be a disadvantage in the case of bacteria identification. It is recommended that the sort of analysis approach should be chosen according to the aim of the study: nested-PCR-DGGE for community complexity analysis, while PCR-DGGE for identification of the dominant bacteria.

The paper deals with the problem of the determination of the effects of temperature on the efficiency of the nitrification process of industrial wastewater, as well as its toxicity to the test organisms. The study on nitrification efficiency was performed using wastewater from one of Polish chemical factories. The chemical factory produces nitrogen fertilizers and various chemicals. The investigated wastewater was taken from the influent to the industrial mechanical-biological wastewater treatment plant (WWTP). The WWTP guaranteed high removal efficiency of organic compounds defined as chemical oxygen demand (COD) but periodical failure of nitrification performance was noted in last years of the WWTP operation. The research aim was to establish the cause of recurring failures of nitrification process in the above mentioned WWTP. The tested wastewater was not acutely toxic to activated sludge microorganisms. However, the wastewater was genotoxic to activated sludge microorganisms and the genotoxicity was greater in winter than in spring time. Analysis of almost 3 years’ period of the WWTP operation data and laboratory batch tests showed that activated sludge from the WWTP under study is very sensitive to temperature changes and the nitrification efficiency collapses rapidly under 16°C. Additionally, it was calculated that in order to provide the stable nitrification, in winter period the sludge age (SRT) in the WWTP should be higher than 35 days.

Photodegradation by sunlight radiation is one of the most destructive pathways for pesticides after

their application in the field. The generated photoproducts can exhibit various toxicological properties and affect non–target organisms. Sulcotrione is a herbicide believed to be a relatively non–toxic alternative to atrazine

herbicides used on corn fields. Despite many tests required for placing plant protection products on the market,

it still happens that transformation pathway and the toxicological profile of these compounds is not fully understood. The results presented in this article are complementary to the research performed by a research group

from National Center for Scientific Research (CNRS) at the University of Blaise Pascal (Auvergne, France).

Sulcotrione is one of main herbicides used to protect the maize plantations in the region of Auvergne (France),

as well as in Poland. As part of the experiments, the distribution of sulcotrione under the influence of polychromatic radiation (fluorescent lamp, l > 295 nm, suitable for environmental tests) in aqueous solution of pH 6.5

was tested. The main products of these reactions were 1H–xanthene–1,9–dione–3,4–dihydro–6–methylsulfonyl

(CP) and 2-chloro-4-methylsulfonyl-benzoic acid (CMBA), which are the result of intra-molecular cyclization

and hydrolysis of sulcotrione, respectively. These products were quantified by using HPLC-diode array detector analysis. The studies clearly show an increase in toxicity towards tested organism (Vibrio fischeri bacteria)

with the increase of irradiation time and appearance of the photoproducts. The results suggest that the observed

increase in toxicity may be rather attributed to the occurrence of the same minor photoproducts than to the

presence of the major photoproducts (CP and CMBA). Identification of the minor photoproducts could not be

performed using the current instrumental equipment.